Method for maintenance of overhead line plants for telecommunications

ABSTRACT

A method for the realisation and the maintenance of overhead line plants for telecommunications, in which the anchor or “mooring” device of the self-gripping two-way supports of the cables, is made integral with a movable structure free to move along the supporting post. The structure comprises a chain allowing to lower the line from span level to ground level, and its successive lifting to the predetermined A operative height at the end of the maintenance intervention; said lowering of the line to the ground level being obtained by expoliting the gravity force acting on the line itself, and the successive lifting, by pulling this anchor chain. The movable structures are realised according to different configurations, depending on the characteristics of the posts where these structures are used.

TECHNICAL FIELD

[0001] The present invention generally refers to the realisation, and tothe execution modalities for operation and maintenance of overhead linesfor telecommunications, comprising a cable sustained by posts, and moreparticularly it relates to movable anchoring or “mooring” devices whichpermit the realisation of the overhead line and the performance ofmaintenance works without the intervention of technicians at a certainheight above the ground.

BACKGROUND ART

[0002] The wide diffusion of the network formed by cables sustained byposts and the realisation modality of these plants, are critical withregard to operation and maintenance, in view of the costs involved, theservice quality, and the safety conditions during the execution of thework.

[0003] These critical aspects are essentially due to the requirement ofthe access of technicians at a certain height above the ground, and todifferent orographic and environmental characteristics of the territorywhere the posts are installed. In fact, besides the stability conditionsof the plants themselves, the actual environmental and orographicfeatures of the territory will determine both the possibility of accessto a position located a certain height above the ground level, and theway this is to be done: use of a controlled platform, a ladder, crampons(climbing irons).

[0004] Naturally, a comparison between the means employed and the timerequired for the work, on the one hand, and the quality of theintervention and the safety of the personnel, on the other hand, leadsto different results, for each modality of access at a certain heightabove ground level, but in all cases they do not lead to optimumresults.

[0005] An object of the present invention is to provide a method ofrealisation of overhead line plants for telecommunications via cable,which radically limits the number of necessary interventions to beperformed by the appointed technicians, at a certain height above theground level.

[0006] A further object of the present invention is to provide a methodallowing the maintenance and the replacement of cables to be performeddirectly from the ground, thereby eliminating the need for access at acertain height above ground level.

[0007] Still another object of the present invention is to provide amethod of realisation and maintenance of overhead line plants fortelecommunications, said plants crossing road paths, and wherein themethod allows the maintenance and the replacement of cables to beperformed directly from the ground, without the need of lowering theoverhead line to the road level and stopping vehicle traffic.

[0008] A last object of the present invention is to provide a method ofrealisation and maintenance of overhead line plants fortelecommunications, which employs standard components, materials andtechnologies in the field of fixed line telephone plants, so that theproposed devices used to carry out the method, will have limited costsand their use is facilitated.

DISCLOSURE OF INVENTION

[0009] These and other objects which will be clarified in thedescription, are obtained by means of a method according to which themooring or anchor device of the self-gripping two-way supports whichsustain the cables, is made integral to a movable structure—and not tofixed points relative to the post by the use of known threaded pins—,wherein the movable structure is free to slide along the sustaining postand comprises a chain allowing to lower the overhead line to thecountryside ground level, and its subsequent lifting at the end of themaintenance intervention. The lowering of the line to the ground levelmay be obtained by exploiting the action of the gravity force.

BRIEF DESCRIPTION OF DRAWINGS

[0010] Preferred embodiments of the invention will now be described forillustrative purposes only, without thereby limiting the generality andpossible applications thereof, by referring in the description to theannexed drawings, in which:

[0011]FIG. 1 is a schematic representation of a complete “mooring” oranchor device, to be applied to a sectioning/junction post, in arectilinear line section with four cables;

[0012]FIG. 2 is a schematic representation of an overheadtelecommunication line extending along a plurality of posts arranged ona rectilinear path;

[0013]FIG. 3 is a schematic representation of a complete mooring oranchor device to be used on a corner post;

[0014]FIG. 4 is a schematic representation of a plurality of fittings oraccessories in a movable mooring or anchor device;

[0015]FIG. 5 is a further schematic representation of an overhead linefor telecommunications, extending along a plurality of posts, with achange in direction of the line and a difference in height of theterrain between the posts 5 p and 6 p;

[0016]FIG. 6 is a schematic representation of an accessory or fitting,having a the shape of a collar;

[0017]FIG. 7 is a schematic representation of an overhead line fortelecommunications, comprising a crossing section;

[0018]FIG. 8 is a schematic representation of a further set of devices,accessories or fittings, for a movable mooring device;

[0019]FIG. 9 is a schematic representation of a cable-supporting device,and of the associated pin with the sustaining ring;

[0020]FIG. 10 is a further schematic representation of an overhead linefor telecommunications, which extends along a plurality of posts, usedto explain the steps of an intervention in which a cable is removed fromthe corresponding buckle.

MODES FOR CARRYING OUT THE INVENTION

[0021] First of all, it must be noted that for clearness purposes thedifferent views have been schematically drawn, in such a way thatconstructive details, whose presence is obvious but which are notrelevant for the description of the relative embodiment, have beenomitted from the views, and in the latter the same component is alwaysdenoted by the same numeral.

[0022] According to the kind of post, and to the function it performs,different realisations of specific, movable mooring (anchoring) devicesare provided, all having—however—the fundamental object to allowmaintenance works to be performed without the need of acceding to aposition at a certain height above the ground level.

[0023] Therefore, it is advisable to consider first of all, thedifferent types of posts present in an overhead line fortelecommunications, which is used for cable transit and for relatedfunctions.

[0024] The line branches off from a starting post, which sustains theshunt (or branch) box used for the branching off of the cables to theuser; usually, according to the law in force, a number of cables between1 and n, may branch off from said box.

[0025] Instead, a transit post is characterised only by the feature ofhaving a cable support buckle at its apex, at the span height; inpractice, its only function is to support the cable span (cable bay).

[0026] A corner post is a post allowing a deviation of the line. Infact, the latter may be forced to deviate from the normal rectilinearpath, thereby changing its direction, due to terrain morphology or forany other reason.

[0027] Moreover, it must be noted that cable coils (skeins) have alength of 300 m, while the distance from one post to the next (usuallycalled span) varies between 35 and 40 meters, so that, in practice,every eight posts there is a cable coil termination.

[0028] Therefore, a junction post is defined as a post where the end ofthe arriving cable coil is connected to the starting portion of a newcable coil termination.

[0029] A sectioning post, is a particular kind of post comprised amongthe eight posts which usually define the 300 m-long cable section (itmay for instance be located 150 m away from the starting post), and itis provided for the following purposes:

[0030] to carry out tests, and

[0031] in order to be able to intervene, depending on the location ofthe failure, by replacing only a limited cable section instead of thewhole section of coil length.

[0032] Moreover, it must be stated beforehand that in already existingoverhead lines there is usually used at least a couple of self-pressingor self-gripping two-way supports, whose function substantially amountsto tensioning the cable, besides making available a certain amount ofcable stock length for the performance of cutting or reconnectingoperations in the course of maintenance works.

[0033] In the posts according to the prior art, said self-pressing orself-gripping two-way supports are—in fact—mounted in a fixed manner ona post, since the access by a technician, to a position located acertain height above the ground, is taken for granted, both during therealisation of the telecommunication line itself, when the cable is laidon the self-gripping support, and during the subsequent maintenance ofthe same.

[0034] The method according to the present invention, while resortingagain to the use of self-gripping two-way supports, provides for amovable anchoring thereof on the post, so that, after all, it will beshown how the cable and its supports may be made to descend to theroad/field (ground) level, thereby allowing a maintenance operation tobe performed at ground level.

[0035] In order to simplify the description of the embodiments of theinvention, it is advisable to consider first of all—among the differentimplemented embodiments—, a particular structure which provides for theuse of an integrated device assembly, in order to carry out themaintenance method of overhead line plants for telecommunications, bythe use of a movable mooring (anchoring) apparatus. In the following,reference will be made to a structure mounted on the sectioning/junctionpost, which is used for possible ordinary maintenance works, and onlyafterwards we will discuss other types of embodiments.

[0036] The rectilinear line section is only a particular typologyconsidered by the present invention, and in this specific case the lineis characterised by the transit of four cables, so that the stressesinvolved, acting on the anchoring or mooring devices, are four timeshigher than for line sections supporting a single cable. For thisreason, it is necessary that the technician is enabled to perform themaintenance work on the line, after the latter has been transferred tothe ground level, without any sort of unbalances being present in thetraction forces exerted between the cables of the line.

[0037] For instance, during the cutting and replacement operations of asingle cable among the four actually present on the line, the latterwould be subjected to a traction in one direction, higher than inanother one, and this unbalance of the forces present on the line, wouldcertainly render more difficult the operation to be performed by atechnician.

[0038] For these reasons, and in particular for the rectilinear sectionof the line, there is provided an anchoring or mooring device accordingto the present invention, which is positioned on the sectioning/junctionpost by the use of a chain of 2.50 m of length, which—as shown in FIG.1—supports a sort of small cage comprising an anchor element 21, in theform of an inverted “U”; on the latter, there are welded two spacers22′, 22″ with an elliptical, flattened configuration, which are hookedby four self-gripping supports 3′, 3″, 3′″, 3″″. This device is in facteffective for supporting even a greater number of cables and lines onthe same post.

[0039] The chain 25 may slide through the upper pin-ring 27′ and thelower pin-ring 27″, thereby allowing lowering or lifting of the spanlevel. Moreover, the chain 25 is fixed to two special hooks, being firstengaged with the hook retainer 28 at a level of about 4.50 m, andextending thereafter upwards to a height of 5.00 m, where it isultimately fixed by means of a safety hook which is not shown in FIG. 1,since it is disposed on the rear side of the post considering theorientation in this figure.

[0040] The disconnection of the chain from these two retainers, and thelowering of the span to a level corresponding to the height of a humanbeing, will only be possible by the use of a rod carrying a specificmeans or attachment.

[0041] Therefore, basically, it is possible to distinguish between twospecific positions of the line at a sectioning/junction post, that is:

[0042] I) line is operative at the span position, wherein the chain 25sustains four self-pressing or self-gripping supports 3′, 3″, 3′″, 3″″,and is fixed by a first retainer 28 and by a second—safety—retainerwhich are both fixedly arranged on the post, the first of said retainersbeing located at a lower level than the second one;

[0043] II) the line is in the lowered state, or “maintenance state”,wherein the chain 25 which still supports the four self-gripping devices3′, 3″, 3′″, 3″″ by means of the small cage 21, has been disengaged fromsaid retainers and has been made to slide, while hooked by a small ropeprovided with a spring catch, in order to be lifted again at the end ofthe maintenance operation.

[0044] From the strict point of view of the design, taking also accountof the order of magnitude of the distances involved in this application,the two anchor rings 27′, 27″ may be fixed at a height of 5.50-6.20 m,spaced apart from each other by a vertical distance of 10 cm, the saidrings being used for receiving the movable mooring—or anchor—devicehaving a cage-like configuration 21, whose lateral ends are hooked bythe self-pressing or gripping supports 3′, 3″, 3′″, 3″″ carrying thearriving line (incoming line) and the outgoing line.

[0045] The retainer 28 and the safety retainer, are both fixed on thesame post, at a height comprised in the interval 4.50-5.00 m.

[0046] The end 21 of the “mooring device”, is anchored to the chain, andthe latter, after having been unhooked, while sliding through the rings,allows lowering or lifting of the line. Under stability conditions thechain is fixed, in a stretched state, to both the fixing retainer andthe safety retainer.

[0047] The use of this “mooring” or anchor device may be betterillustrated if reference is made to FIG. 2, corresponding to a method ofuse of the disclosed devices. In particular, said figure schematicallyshows a sequence of posts arranged along a rectilinear path, wherein theequidistant posts denoted by E and I are considered to besectioning/junction posts, while the remaining posts, are considered tobe, for greater clearness, only transit posts.

[0048] Thus, supposing a failure has been noted and localised in thecable section extending from I to E, then, the following steps must beperformed during the intervention:

[0049] 1) the technician approaches the post E, and using the specialrod equipped with a rope sustaining support and a section breakingdevice—the latter being widely described later on—, hooks the chain andreleases it from the safety retainer;

[0050] 2) he removes the small rope from its support on the rod, andwhile exerting a small downward traction force, he releases the chainfrom the retainers where it is anchored;

[0051] 3) the release of the chain causes the lowering of the line to alevel corresponding to the normal height of a human being; then, thetechnician locks—if necessary—the movable mooring device by means of alocking strap, and he cuts the damaged or broken cable;

[0052] 4) he “temporarily” joins a new cable to the old one to bereplaced;

[0053] 5) he unhooks the chain from the post I as described in the aboveparagraphs 1, 2 and 3, he cuts the damaged or broken cable, and recoversthe cable section to be replaced, up to the temporary junction carryingthe new cable;

[0054] 6) he joins the new cable to the outgoing one, and using thechain, he brings the movable mooring device again to its seat at theapex of the post; he hooks the chain to the fixing retainer andthereafter to the safety retainer, and then he puts the small rope againin its position in the special support provided on the rod, and unhooksthe small rope from the chain;

[0055] 7) at the post E, the technician snubs the replaced cable andfixes it to the self-gripping or self-pressing support; thereafter, hehooks the self-gripping support to the movable mooring device andperforms the cable jointing operation, thereafter he releases themooring device if it was locked, and brings it again to its seat in thering shaped hook at the top of the post;

[0056] 8) he fixes the chain to the fixing and safety retainers, and herecovers the small rope as described in paragraph 6).

[0057]FIG. 3 exemplifies a movable mooring device for a corner post,which substantially operates according to the above described stepsconcerning a movable mooring device for a sectioning/junction post, butwhich has specific features distinguishing it both functionally andstructurally.

[0058] In fact, as schematically shown in FIG. 3, the couple ofself-gripping or self-pressing supports 3′, 3″ is respectively anchoredor “moored” on two supporting eyelets, 4′, 4″, which form the endelements of a chain-guide 5, which may slide through a ring 6 rigidlyconnected to the post, thereby allowing the lowering of the line locatedat the span level, to the ground level, and the subsequent lifting atthe end of the maintenance intervention. The outer diameter of eacheyelet 4′, 4″ exceeds the inner diameter of the ring 6, in order toprevent their sliding through the ring itself, when the line is liftedagain to its upper level.

[0059] Therefore, basically, it is possible to distinguish two differentspecific positions of the cable and its supports:

[0060] I) the line is in its operative position at the span level, wherein the chain 5 sustains the two self-gripping supports 3′, 3″ and thechain 5 itself is retained by means of a first, or fixing retainer 9′,and by a second, or safety retainer 9″, which are both arranged in fixedpositions on the post, wherein one of the retainers is located above theother and their mutual angular distance corresponds to 90°; the saidelements 9′, 9″ for preventing the chain from sliding, are substantiallyconfigured in such a way as to comprise a flat portion to be fixed tothe post surface, and an outgoing portion having two branches 8′, 8″which widen outwardly in a flaring configuration, thereby allowing toreceive the chain 5 and retain the latter, when it is pushed to theinside of limited width of the bifurcation 8′, 8″; chain sliding iseffectively prevented by the fact that the lateral dimension of a chainring of the chain 5 is greater than the width of the space between thetwo branches 8, in proximity of the base 7;

[0061] II) the line is in the lowered position or maintenance state,wherein the chain 5, which still sustains both self-pressing supports3′, 3″ by means of the two eyelets 4′ and 4″, has been released fromsaid retainers or locking elements 9′, 9″ and has been made to slidewhile hooked by a small rope provided with an eyelet or loop, in such away as to be able to bring the line again to the upper level, after themaintenance intervention.

[0062] Under a strict point of view of the design, taking also accountof the order of magnitude of the dimensions involved, it is convenientto provide the ring hook 6 on the post at a height of 5.50-6.20 m, andto provide a corner chain 5, which is capable of sliding therein andhaving the two eyelets 4′, 4″, with a length comprised between 1 m and1,20 m, the said chain hooking—as described above—the two self-grippingsupports 3′, 3″ of the line.

[0063] At lower height, of 30-50 cm with respect to the ring hook 6,there is fixed the fixing retainer 9′ and the safety retainer 9″, onwhich the chain is locked.

[0064] In a further embodiment of the chain 5, the latter has an “Y”configuration, that is it as a branching off with two arms, each havinga length of about 10 cm and an end forming an eyelet 4. This kind ofbifurcated configuration of the chain allows its more versatile useunder certain conditions, like the presence of differences in height(unevenness of the ground) or obstacles preventing the technician fromoperating from an optimum position. In fact, in this situation it mayhappen that during the unhooking operation by the technician, the chainwill not be long enough to lower the line to the ground level of thecountryside, since the different pile-driving levels may cause the cableto rise, on one side, for a certain distance. These extensions providedon the end of the chain, have the effect of making available anincreased length and a certain degree of freedom in the movements, so asto facilitate the adjustment of the line through a momentary and movingaway lowering movement or a momentary lifting and moving away movement.

[0065] The release of the chain 5 from its locking elements 9′, 9″, inorder to perform the restoration of the line, and in order to adjust thedescent stroke and lifting stroke of the chain, is obtained by means ofspecial devices.

[0066] The use of these special devices, which will be described below,enables the technician to make these kind of interventions on the line,and prevents at the same time any act of vandalism.

[0067] In particular, in order to carry out the release operation of themooring devices or anchor devices that have been described previously,and in order to perform other kinds of interventions which will beexplained below, the technician avails himself of a telescopic rod 16made of plastic reinforced by fibre glass, and of a set of replaceableterminal supports.

[0068] For carrying out all kinds of interventions, on posts providedwith the above specified equipment, the telescopic rod sustains a hollowtransport device 15, of the kind shown in FIG. 4A.

[0069] This device substantially comprises two elements forming a singlebody:

[0070] a hollow cylinder 14, of a slightly greater diameter than that ofthe telescopic rod 16, in such a way as to be fitted and retainedthereon, and

[0071] a portion of a hollow cylinder 17, which is open on one side,thereby allowing to insert therein a small rope 18 with a loop or eyelet19.

[0072] In practice, when the technician releases or unhooks the line, heintroduces first the loop or eyelet 19 of the small rope, on the hook 20forming the lower termination of the chain 5, by using the telescopicrod; then, he removes the small rope 18 from its seat 17, and uses thesmall rope in order to unhook the chain 5 from the retainers 9′ and 9″.Thus, the chain 5 will be free to slide and will enable the lowering ofthe line under the action of its own weight, whereas the liftingoperation and the locking in the retainers 9′ and 9″ may be performed atthe end of the intervention, by pulling the small rope and therefore thechain 5 connected thereto by means of the hook 20.

[0073] Moreover, this telescopic rod is provided with a section breakingdevice, as shown in FIG. 4B, that is of a special element used toprevent undesirable oscillations and flexion of the support rod, duringthe various uses of the rod at a certain height above the ground level,both when the latter sustains an anchor or release device, and when itsustains a device for the introduction of the cable at the time the lineis realised, as disclosed below.

[0074] From the structural point of view, this section breaking deviceforms a removable half-collar 30, which is fixed, depending on the kindof intervention, in an approximately intermediate and adjustableposition on the rod—which is in fact 4 to 5 meters long—, in order toallow to perform an intervention at a predetermined height. Actually,due to this high length value, the rod could be subjected to flexion oroscillations, so that the arrangement of said section breaking device,provided with a concave portion 31 of the half-collar which faces thepost and leans against it in a stable position, has the effect ofeliminating said undesirable flexion and oscillations. The use of themooring devices which have just been described, may be better understoodwith reference to FIG. 5, which refers to an intervention on a sectionof the line, which includes a difference in height and a change indirection.

[0075] In the situation which is schematically shown, it is supposedthat the lowering of the overhead line to the ground level of thecountryside, is performed by means of a chain with two arms, provided onthe post 5 p, at which location the line changes in direction andcrosses a road of a farm.

[0076] Supposing the existence of a failure at 150 m, it is decided toreplace the cable section starting at the distributor supporting postand ending at the post 5 p. Then, the following operative steps may beidentified:

[0077] 1) the technician approaches the post 5 p, and by means of thespecial rod, equipped with the small rope support and with the sectionbreaking device, hooks the chain and releases it from the safetyretainer;

[0078] 2) he removes the small rope from the small rope support on therod, and by means of a pulling action exerted first externally and thenupwardly, he unhooks the chain from the fixing retainer;

[0079] 3) the release of the chain causes the lowering of the line tothe ground level, so that the damaged cable to be replaced may beremoved from the self-pressing support and may be cut; then, the linecan be brought again to a safety level by fastening the small rope atthe post base; subsequently, a new cable is “temporarily” jointed to theold cable to be replaced;

[0080] 4) at the location of the distributor-supporting post, 1 p, theself-gripping or self-pressing support is released from the small bandwhich retains the elliptic collar—see details below—;

[0081] 5) the old cable to be replaced is recovered up to the temporaryjoint which holds the new cable;

[0082] 6) at the location of the post 5 p the line is once again loweredto the ground level, the new cable is jointed to the outgoing one,whereafter the line is again lifted to the operative level;

[0083] 7) the chain is hooked to the fixing retainer 9′ and to thesafety retainer 9″, in this order, and then the small rope is againinserted inside the special support on the rod, and is released from thehook 20 forming the lower termination of the chain;

[0084] 8) at the location of the distributor support post, 1 p, thecable is snubbed and fixed to the self-pressing support, while thelatter is hooked to the small band which retains the elliptic collar;

[0085] 9) the small cable is connected to the distributor.

[0086] For what concerns the equipment of the starting post, on theother hand, the problem briefly amounts to the fact that the lattersupports four cables which are connected—that is screwed—to adistribution box, and are made to extend upwardly, till they reach theline span level; in conventional overhead lines, the said box is fixedat 3.50 meters, and the cable extends upwards to a height of 5.50meters, in order to be introduced inside the self-gripping, two-waysupport. More specifically, these cables extend from a terminal boardand are lodged inside a plastic-made protection raceway, which reachesthe top of the post, where the cables of the span are tensioned by meansof the self-gripping two-way supports, which are fixed by means of athreaded pin to the post itself, at the span level. Due to the fact thatthese pins are permanently driven in the post, the mooring device isitself fixed, so that the self-gripping two-way device can in no way beremoved, lowered to the ground level, and lifted again to the operativeposition.

[0087] According to the method devised by the present invention, theself-gripping support is not fixed anymore at the upper position,integral to the pin, but is fixed instead to a collar of the kindillustrated in FIG. 6; in practice, above the distributor, and at aheight of 3.30 m, there is fixed an elliptic collar 32 with bandretainer, to which there is anchored a couple of self-gripping supports,supporting one or more cables, whereas at a height of between 5.50 and6.20 meters, there is positioned a mesh collar for hooking the two-waycable guide, for the transit of the line at span level. The ellipticcollar 32 comprises two half-collars, which enclose the wholecircumference of the post. FIG. 6 shows the most significant half-collar34, for the purpose of the invention, which is characterised by the factthat it comprises a support structure for the self-gripping devices. Infact, the three projecting small rods 35′, 35″, 35′″, and thetransversally inserted rod iron 36, make up the hooking element for theself-gripping supports, as the rod iron 36 is separated by the centralprojecting element 35″ in two distinct sections, each of which maysupport a self-gripping two-way device.

[0088] Since the latter is arranged at a height of 3.30 meters, thetechnician may reach said supports by using a single ladder element,thereby noticeably reducing the risks of the intervention. Moreover, theaccess of the technician at a height of 3.30 m is already foreseenduring ordinary maintenance, since the technician must in any case reachthe terminal board in order to perform ramification (branching-off)interventions: therefore, he may in the same way have access to thecollar 34 in order to effect maintenance interventions on the startingpost.

[0089] The collar has been realised in such a way as to be capable ofsupporting two self-gripping two-way devices, and since eachself-gripping device is suited to hold two cables, it is possible toimplement a line with four cables, complying in this manner with thebody of technical rules, according to which the number of single cablesmust be less than five in the realisation of subscriber's overheadlines.

[0090] The collar described in the above section and used in a startingpost, is also of fundamental importance for the equipment of posts usedin overhead lines crossing roads or the like.

[0091] In fact, also in this application, the elliptical collar 32 withband retainer is fixed at a height of 3.30 meters, and the twoself-gripping supports which support the line, are anchored thereon.

[0092] At a height comprised between 5.50 m and 6.20 m, there is fixed afurther elliptical collar, and to the latter there is fixed the steelrope which supports, by means of clamps or clips, a PVC tube containingthe overhead line which crosses the road. At a smaller height, there ispositioned the mesh collar, to which there are hooked the incoming andoutgoing two-way cable guides.

[0093] To carry out the intervention on the line section, in order toreplace the cable on a crossing cable span, the following two steps areprovided for, as schematically shown in FIG. 7:

[0094] the technician approaches a first post 12 p and releases thedamaged cable to be replaced from the self-gripping device, he cuts thecable and temporarily joints it to a new cable;

[0095] he approaches the other post 13 p, releases the damaged cablefrom the self-gripping device, and pulls it towards himself until hefinds the temporary joint which carries the new cable;

[0096] he fixes the new cable on the self-gripping device and hedefinitively joints it to the outgoing (continuing) cable;

[0097] he goes back to the post 12 p, snubs the cable, fixes it in theself-gripping device, and effects the definitive joint with the outgoingcable extending in the other direction;

[0098] In FIGS. 8A and 8B there are shown further accessories or devicesused for the realisation of the apparatus of the invention. FIG. 8Ashows the telescopic rod carrying the special section breaking device30.

[0099] The telescopic rod, in this case, carries at its distal end abuckle-supporting and probe-guiding support, which is bent to an “L”shape and has an exit aperture 41 which is cut away and flared. Thisspecific configuration of the device allows to receive the cablesupporting buckle 71 of FIG. 9, and moreover, the introduction of aprobe which is made to slide inside the cable supporting buckles 71 ofthe transit posts, carrying directly from the ground the cable to beinstalled or replaced, till it reaches its predetermined position.

[0100] Particularly for the starting posts, the probe-guiding support 40has the most advantageous configuration in order to insert the probe andthe cable, together, inside a sleeve 42 of the kind shown in FIG. 8B,which may be oriented and which is anchored to a hook of the post bymeans of the ring 43.

[0101] The use of the devices which have been just described, may bebetter understood by referring to FIG. 10, for instance, whichexemplifies a maintenance intervention of cable replacement, when thelatter has come out of the buckles due to mechanical breakage, whereinthe following steps are provided for:

[0102] 1—at the post 24 p, the technician lowers the line to thecountryside ground level, and cuts the cable to be replaced;

[0103] 2—at the central post 23 p the technician, by using thetelescopic rod and a probe-guiding support, causes the probe to slideinside the cable-supporting buckle 71, from the left to the right, thatis, with regard to FIG. 10, in the direction from 23 p towards 24 p;

[0104] 3—he temporarily joints the new cable to the head of the probe;

[0105] 4—he pulls the probe again in order to thread the cable in thebuckle;

[0106] 5—he goes to the post 22 p which precedes the central post 23 pand repeats the operation already described;

[0107] 6—at the post 21 p he lowers the line to the countryside groundlevel, he cuts the old cable and joints the new one to the outgoingcable (cable continuation) and he lifts the overhead line back to thespan level;

[0108] 7—he goes to the post 24 p, snubs and fixes the new cable to theself-gripping device, he realises the joint with the outgoing cable, andfinally brings the line again to the operative position.

[0109] Industrial Applicability

[0110] Interventions performed for test purposes, on the plantsinstalled as described above, have lead to optimum results with regardto the total time needed for the intervention, and with regard to theeffectiveness of the final result of the intervention. It is obviousfrom the description, that the system is versatile and is certainly notconfigured for a single typology of posts. Taking account of the varietyof orographic conditions of the terrain where the posts are installed,it may be noted that the system disclosed by the present invention hassolved all possible cases which may arise in practice (although itfrequently happens to have the possibility to work on a completelyrectilinear section of the line, this situation may be onlytheoretically generalised to all situations, since technicians oftenhave to deal with continuos changes in direction, road crossings,difference in height due to orographic reasons, environmentmodifications, etc.). A further advantage may be seen in the modularityof the devices of the present invention, so that the technician whoknows the kind of intervention and the type of section where the latteris to be performed, may select in advance the set of devices he needs.In any case, the greatest advantage is obtainable when the complete setof devices is available, since a single technician is thereby enabled toalways perform resolutory operations at the time of first interventionand under completely safe conditions, even if he does not know inadvance neither the kind of failure or defect, nor thetechnical/environmental condition of the posts and of the terrain.

1*. A movable apparatus, for “mooring” or anchoring the self-grippingsupports in a telecommunication line for the realisation and maintenanceof overhead line plants for telecommunications, in which the mooring oranchor device of the self-gripping two-way devices which carry thecables, is made integral to a movable structure, which may freely slidealong the sustaining post, said structure comprising an anchor chain(25), allowing to lower the span line to the countryside ground leveland its successive lifting to the operative position at the end of themaintenance intervention; said lowering of the line to the ground levelbeing obtained by exploiting the gravity force acting on the lineitself, and the subsequent lifting to the operative position of saidmooring or anchor device, being obtained by a traction of said anchorchain exerted by the operator, said apparatus being, characterised inthat it is positioned on a sectioning/junction post and in that itcomprises a chain supporting an anchor element (21) having an inverted“U” configuration, on which there are welded two spacers (22′, 22″) witha flattened elliptical shape, which are hooked by four self-grippingsupports; the said chain being apt to slide through an upper, shaftbearing ring (27′), and through a lower, shaft bearing ring (27″), inorder to allow the lowering or the lifting of the span level, and thesaid chain being fixed to two special hooks, that is, locked in a firstposition to a hook (28) at about 4.00 meters of height, and in afurther, more elevated position, at about 5.00 m, to a second hook, inwhich it is definitively fixed. 2*. A movable apparatus, for “mooring”,that is, for anchoring the self-gripping supports in a telecommunicationline, according to claim 1*, characterised in that said chain has alength of 2.50 meters. 3*. A movable apparatus for “mooring”, that isanchoring, the self-gripping supports in a telecommunication line,characterised in that it is located on a corner post, and in that itcomprises a couple of self-gripping supports respectively moored to twosupport eyelets (4′, 4″) forming end elements of a guide-chain (5),which allows, by sliding inside a ring (6) integral with the post, thelowering of the line from span level to ground level, and its subsequentlifting to the operative position after the maintenance intervention, bythe use of a small rope (18); the said chain (5) being locked by afirst, or fixing retainer (9′), and by a second, or safety retainer(9″), both rigidly connected to the post at different heights; the saidretainers (9′, 9″) for preventing the chain from sliding, comprising aflat portion to be fixed to the surface of the post, and a projectingportion forming a bifurcation (8′, 8″), which widens outwardly and isflared, so as to allow the insertion of said chain (5) and the lockingof the same, once it has been pushed towards the inner narrowed portionof the bifurcation (8′, 8″). 4*. A movable apparatus, for mooring theself-gripping supports in a telecommunication line, according to claim3*, characterised in that said chain (5) has a length of 1.20 meters.5*. A movable apparatus, for mooring the self-gripping supports in atelecommunication line, according to claim 3*, characterised in that itcomprises a chain (5) of 1.20 meters of length, having an “Y”configuration, including a ramification with two arms, each having alength of the order of 10 cm and ending respectively in an integrallyformed eyelet. 6*. A movable apparatus, for mooring the self-grippingsupports in a telecommunication line, according to claims 1*-5*,characterised in that it comprises telescopic means allowing the accessto the post and the respective mooring device, and suited to interactwith a set of interchangeable supports, including a device with a hollowdouble cylinder (15), a buckle-supporting and probe-guiding support (40)and a section breaking device (30). 7*. A movable apparatus, for mooringthe self-gripping supports in a telecommunication line, according toclaim 6*, characterised in that the hollow double cylinder (15)substantially comprises two integrally formed elements: I—a first hollowcylinder (14) having a slightly greater diameter than the diameter ofthe telescopic rod (16), so as to be fitted and retained on the latter,and II—a section of a hollow cylinder (17), which is open on one side,in such a way to allow the insertion of a small rope (18) which supportsa rope loop (19). 8*. A movable apparatus, for mooring the self-grippingsupports in a telecommunication line, according to claim 6*,characterised in that said section breaking device (30) has aconfiguration similar to a removable half-collar, which is fixed,according to the kind of intervention, in an approximately intermediateand adjustable position along the telescopic rod, in order to ensure itssafe use at a certain height above the ground level eliminating anyflexion or oscillations of the rod; the said section breaking devicebeing positioned so as to face the post with the concavity of itshalf-collar, thereby leaning on it and ensuring its stability. 9*. Amovable apparatus for mooring the self-gripping supports of atelecommunication line, according to claim 6*, characterised in that thebuckle-supporting and probe-guiding support (40) has a bent, “L-shaped”configuration, with its exit opening (41) partially cut away and flared,thereby being suited to receive a cable supporting buckle (71) andallowing the insertion of a probe, which is slid inside the cablesupporting buckles of the transit posts, and allowing to carry the cableto be installed or replaced, directly from the ground. 10*. A movableapparatus, for mooring the self-gripping supports in a telecommunicationline, according to any of the preceding claims, characterised in that itfurther comprises an elliptic collar (32) with a retainer band,including two half-collars; one of said collars being provided withthree projecting elements having a transversally inserted rod iron whichforms the anchor element, and the central one (35″) of said projectingelements separating the rod iron in two sections; each of these sectionsbeing suited to support a self-gripping two-way device and itsrespective cables. 11*. A method for the realisation and maintenance ofoverhead line plants for telecommunications, characterised in that forthe replacement of a cable in a long, rectilinear line section, thefollowing operative steps are provided for: I—at a first sectioning post(E), the operator hooks and releases the chain from the safety retainer,using said special rod, equipped with the support of the small rope andthe section breaking device; II—the operator removes the small rope fromits support on the rod, and by exerting a slight downward traction,unhooks the chain from the fixing retainer; III—the unhooking, orrelease, of the chain, causes the downward displacement of the line to aheight corresponding to an individual's average height; then, ifnecessary, the movable mooring device is fixed on the post by means of alocking strap, and the damaged cable is cut; IV—the new cable is“temporarily” jointed to the old cable to be replaced; V—the chain isreleased from a second sectioning post (I), as in point I and II, andthe cable is cut and recovered up to the temporary joint carrying thenew cable; VI—the new cable is jointed, and through the chain, themovable mooring device is brought back to its seat at the top of thesecond post; the chain is hooked to the fixing retainer and then to thesafety retainer, and the small rope is inserted again inside its specialsupport on the rod, and finally the small rope is unhooked form thechain; VII—at the first sectioning post, the operator fixes the cable tothe self-gripping support and snubs it; then, the self-gripping supportis hooked to the movable mooring device and the junction is performed;then, the device is released if it was previously fixed, and is broughtback to its seat in the ring hook at the top of the post; VIII—the chainis fixed to the fixing and safety retainers and the small rope isrecovered as in the above step VI. 12*. A method for the realisation andmaintenance of overhead line plants for telecommunications, saidoverhead line plant including a long rectilinear section as in claim11*, and an extended section including a change in direction,characterised in that for the replacement of a cable along said extendedline section including a change in direction, the following steps areprovided for: I—a technician (a) detaches the cable to be replaced, fromthe distributor; II—another technician (b) approaches a corner post (5),unhooks the mooring chain in order to lower the overhead line to thecountryside ground level, releases the old cable to be replaced from theself-gripping support and cuts it; then, he temporarily joints the oldcable to the new one, and brings the line again in its safety positionat a predetermined height; III—the first technician (a) operating fromthe distributor supporting post (1 p), unhooks the self-gripping supportfrom the band retainer of the mooring collar, releases the old cable,and by pulling it towards himself, begins to recover the same; IV—afterhe has found the temporary joint carrying the new cable, the technician(a) releases it and communicates this fact to the other technician (b),V—the technician (b), from the post (5 p), lowers the line again to thecountryside level, and locks the cable in the self-gripping support,effects the definitive joint, brings the line again to its operativeposition at the predetermined height above the ground, and finally fixesthe chain to the fixing and safety retainers; VI—from the distributorsupporting post, the technician (a) snubs the cable, hooks theself-gripping support to the mooring or anchoring collar, and performsthe electrical connection of the line in order to restore the service.13*. A method for the realisation and maintenance of overhead lineplants for telecommunications, according to claims 11* or 12*, saidoverhead line plants including a section thereof which crosses a road,characterised in that for the crossing of roads or the like, a PVC tubeis used which has an internal diameter of a size allowing the transit ofcables, so that the repair/ replacement of these cables may be performedwithout being forced to lower the line to the road level, and thereforewithout blocking the vehicle traffic. 14*. A method for the realisationand maintenance of overhead line plants for telecommunications,according to claim 13*, characterised in that for the replacement of acable at a crossing span, the technician makes use of the followingsteps, while working at the distributor's height: I—at the location ofthe first crossing post (12 p), he releases from the self-grippingsupport arranged at the distributor level, the damaged or broken cableto be replaced, he cuts it, and temporarily joints the new cable; II—hegoes to the other post (13 p), releases the damaged or broken cable fromthe self-gripping support located at the distributor level, and pulls ittowards himself, until he finds the temporary joint carrying the newcable; III—he locks the new cable on the self-gripping support andeffects the definitive joint; IV—he goes back to the initial post (12p), snubs the cable, locks it in the self-gripping support, and performsthe definitive joint.